GW Observatory data are not always available. In addition, there are
times when data may be available, but of poor quality. For these
reasons, most work with gravitational-wave data begins with a "segment
list", specifying the times of data to be analyzed.
Types of segments
GW Observatory data contain a variety of segment types, but there are
generally three types:
The segments that include DATA (e.g.
H1_DATA) indicate strain availability.
Segments denoted with CAT indicate problems with the
data. There are several CAT severities indicated by an
integer (e.g. H1_CAT1, H1_CAT2,
H1_CAT3; CAT1 being the worst).
Hardware injections are marked with HW_INJ. For more
information, see the Data Quality Segments heading on the
O3b run documentation.
Finding Segment Lists with Timeline
Pick a dataset and the page will reload to adjust the GPS times
for the whole duration of the dataset.
You can adjust the GPS interval you are interested in by changing
In the strain file section, you can download strain files for the
run and GPS interval defined in the previous step.
Click the buttons with the corresponding detector to download from
the archive page.
Note: Strain links are not available for event segments. You can
find strain files for events on the Event Portal page for each
To visualize the timeline segments, select the checkboxes for the
segments you want to visualize and click on the
A new page will open in a new tab with the segments on an
To retrieve the segments in a JSON format, click on the JSON tab
and then click on the segment of interest. The list of segments
will open in a new tab.
You can inspect the segments on the "segments" key.
The button All Timelines will show all the timelines
available for the dataset as a single JSON list.